This invention relates to mechanical joints for double containment pipes and fittings and to methods for making such joints.
Double containment pipes are in common use for transporting contaminants and toxins underground. They are most commonly used as underground gasoline transporting pipelines. A double containment pipe is in essence a pipe within a pipe. An annulus is formed between the pipes. An inner, or primary, pipe is the carrier of the fluids while the outer, or secondary, pipe is used to contain any leakage from the primary pipe. Most commonly, these pipes are made from rigid fiberglass.
In order to connect the corresponding primary and secondary pipes of consecutive double containment pipes, it is required that the pipes be shaved prior to bonding. Moreover, it is very difficult to bond joints in cold wet climates. Consequently, the costs for bonding double containment pipes are excessive, and the quality of the joints is not consistent. As a result, there has been a noticeable decline in the use of fiberglass double containment pipes. Instead, flexible hoses requiring no bonding have taken a significant market share, even though they are more expensive than fiberglass double containment pipes. The reason for the emergence of these flexible hoses is that they can be easily connected together in cold, wet weather.
Accordingly, there is a need for a mechanical joint for joining double containment pipes that can be easily applied under cold, wet climates.